During muscle contraction, calcium binds to Group of answer choicestroponinactinmyosintropomyosin

Muscle Contraction and Calcium Binding

During muscle contraction, calcium ions (Ca²⁺) play a critical role by binding to a specific protein complex in muscle fibers. The correct answer to your question is troponin.

1. Role of Calcium in Muscle Contraction:

   • Calcium is released from the sarcoplasmic reticulum into the cytosol when a muscle cell is stimulated.
   • When calcium binds to troponin, it causes a conformational change in the troponin complex.

2. Effects of Calcium-Troponin Binding:

   • This change in shape moves tropomyosin away from the myosin-binding sites on actin filaments.
   • As a result, myosin heads can attach to actin, leading to the cross-bridge formation, which is essential for muscle contraction.

In summary, calcium binds to troponin during muscle contraction, facilitating the interaction between actin and myosin, which results in muscle shortening and force production.